MediaSourceDelegate: Fix DecryptingDemuxerStream initialization logic.

Different CDMs are supported differently. For CDMs that support a Decryptor, we'll try to use DecryptingDemuxerStream in the render side. Otherwise, we'll try to use the CDMs in the browser side. Therefore, if DecryptingDemuxerStream initialization failed, it's still possible that we can handle the audio with a CDM in the browser. Declare demuxer ready now to try that path. Note there's no need to try DecryptingDemuxerStream for video here since it is impossible to handle audio in the browser and handle video in the render process.

This also fixes the issue where CdmAttachedCB is fired twice with "false".

BUG=578203
TEST=No DCHECK when playing media/L3_audio_L3_video.mp4.mpd.

Review URL: https://codereview.chromium.org/1613793002

Cr-Commit-Position: refs/heads/master@{#372842}
(cherry picked from commit e261467)

Review URL: https://codereview.chromium.org/1659013002 .

Cr-Commit-Position: refs/branch-heads/2623@{#234}
Cr-Branched-From: 92d7753-refs/heads/master@{#369907}

Author: xhwang-chromium

content/renderer/media/android/media_source_delegate.cc

@@ -153,6 +153,12 @@ void MediaSourceDelegate::InitializeMediaSource(
     const base::Closure& waiting_for_decryption_key_cb) {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
   DCHECK(!media_source_opened_cb.is_null());
+  DCHECK(!encrypted_media_init_data_cb.is_null());
+  DCHECK(!set_cdm_ready_cb.is_null());
+  DCHECK(!update_network_state_cb.is_null());
+  DCHECK(!duration_change_cb.is_null());
+  DCHECK(!waiting_for_decryption_key_cb.is_null());
+
   media_source_opened_cb_ = media_source_opened_cb;
   encrypted_media_init_data_cb_ = encrypted_media_init_data_cb;
   set_cdm_ready_cb_ = media::BindToCurrentLoop(set_cdm_ready_cb);
@@ -496,16 +502,14 @@ void MediaSourceDelegate::OnDemuxerInitDone(media::PipelineStatus status) {
   audio_stream_ = chunk_demuxer_->GetStream(DemuxerStream::AUDIO);
   video_stream_ = chunk_demuxer_->GetStream(DemuxerStream::VIDEO);
 
-  if (audio_stream_ && audio_stream_->audio_decoder_config().is_encrypted() &&
-      !set_cdm_ready_cb_.is_null()) {
+  if (audio_stream_ && audio_stream_->audio_decoder_config().is_encrypted()) {
     InitAudioDecryptingDemuxerStream();
     // InitVideoDecryptingDemuxerStream() will be called in
     // OnAudioDecryptingDemuxerStreamInitDone().
     return;
   }
 
-  if (video_stream_ && video_stream_->video_decoder_config().is_encrypted() &&
-      !set_cdm_ready_cb_.is_null()) {
+  if (video_stream_ && video_stream_->video_decoder_config().is_encrypted()) {
     InitVideoDecryptingDemuxerStream();
     return;
   }
@@ -519,7 +523,6 @@ void MediaSourceDelegate::InitAudioDecryptingDemuxerStream() {
   DCHECK(media_task_runner_->BelongsToCurrentThread());
   DVLOG(1) << __FUNCTION__ << " : " << demuxer_client_id_;
   DCHECK(!set_cdm_ready_cb_.is_null());
-
   audio_decrypting_demuxer_stream_.reset(new media::DecryptingDemuxerStream(
       media_task_runner_, media_log_, waiting_for_decryption_key_cb_));
   audio_decrypting_demuxer_stream_->Initialize(
@@ -547,10 +550,22 @@ void MediaSourceDelegate::OnAudioDecryptingDemuxerStreamInitDone(
   DVLOG(1) << __FUNCTION__ << "(" << status << ") : " << demuxer_client_id_;
   DCHECK(chunk_demuxer_);
 
-  if (status != media::PIPELINE_OK)
+  if (status != media::PIPELINE_OK) {
     audio_decrypting_demuxer_stream_.reset();
-  else
-    audio_stream_ = audio_decrypting_demuxer_stream_.get();
+    // Different CDMs are supported differently. For CDMs that support a
+    // Decryptor, we'll try to use DecryptingDemuxerStream in the render side.
+    // Otherwise, we'll try to use the CDMs in the browser side. Therefore, if
+    // DecryptingDemuxerStream initialization failed, it's still possible that
+    // we can handle the audio with a CDM in the browser. Declare demuxer ready
+    // now to try that path. Note there's no need to try DecryptingDemuxerStream
+    // for video here since it is impossible to handle audio in the browser and
+    // handle video in the render process.
+    is_demuxer_ready_ = true;
+    NotifyDemuxerReady();
+    return;
+  }
+
+  audio_stream_ = audio_decrypting_demuxer_stream_.get();
 
   if (video_stream_ && video_stream_->video_decoder_config().is_encrypted()) {
     InitVideoDecryptingDemuxerStream();